基于拉曼散射的光纤分布式温度测量系统的空间分辨力

基于自发拉曼散射的光纤分布式温度测量系统是一种真正的分布传感系统且已商品化。本文从光学的角度出发较详细地分析了此类系统的空间分辨力理论极限及其影响因素。分析表明， 对于一个１ ｋｍ 的多模系统， 若接收机的最小可分辨光功率优于３．５ ｐＷ， 则其在０～４００℃的范围内且温度精度为±１℃时的空间分辨力极限为２ ｃｍ ； 当接收机的最小可分辨光功率小于０．５ ｐＷ， 单模系统的空间分辨力极限优于对应的多模系统。因此， 把基于自发拉曼散射机理的光纤分布式温度测量系统用于短距离高分辨力的系统理论上是可行的。

Spatial Resolution Limit of A Raman Distributed Optical Fibre Temperature System

So far, a truly distributed and commercialized optical fiber temperature system is based on Raman scattering. The spatial resolution limit of such a system is analyzed in the view of nonlinear fiber optics. It is found that a spatial resolution of 2 cm can be achieved for an 1km multi-mode system of 3.5 pW sensitivity and temperature resolution of ±1℃ within 0～400℃. With a sensitivity of better than 0.5 pW, the spatial resolution of a single-mode system will be better than that of above multi-mode system. Theoretically there is no restriction to introduce such a system into the application of moderate distance and high spatial resolution.